Idiopathic Giant Cell Myocarditis: State of the Art

Abstract

Giant cell myocarditis (GCM) is a rare, rapidly progressive and highly lethal disease in young and middle-aged adults. It is attributed to an inflammation of the heart muscle, and mediated by T lymphocytes and anti-myosin autoantibodies. Making diagnosis of GCM with multiple noninvasive imaging modalities is possible in a small percentage of patients, so myocardial tissue diagnosis is often required. An early diagnosis is very important, because immunosuppressive treatment may significantly improve clinical course and survival of these patients. GCM often escapes diagnosis until autopsy or transplantation and has defied proper treatment trials for its rarity and deadly behavior. This review will focus on the diagnostic approach to patients with suspected GCM and currently evidence-based treatment strategy for this disease.

Giant cell myocarditis causing refractory ventricular tachycardia in a pediatric patient

“…Unfortunately, echocardiogram and magnetic resonance imaging of heart could not differentiate between GCM and other forms of myocarditis, but they are helpful in differentiating fulminant versus acute myocarditis . In our patient, both echocardiogram and MRI failed to diagnose even myocarditis in the early phase of the disease.…”

“…Saltykow first described nontuberculosis, nonsyphilis associated GCM in 1905. Since then cases of GCM have infrequently been reported.…”

“…Up to 20% of patients with GCM have other autoimmune conditions such as thyroiditis, inflammatory bowel disease, rheumatoid arthritis . Further studies distinguished GCM from sarcoidosis, both histologically and clinically . Pathologically, GCM will have diffuse or multifocal infiltrate consisting of lymphocytes and eosinophils with multinucleated giant cells at the periphery and various degree of fibrosis and damaged myocytes .…”

“…Methylphenidate could have caused his ventricular arrhythmia, although it is highly unlikely given the unremarkable first 4 years of its use and now with the sudden onset of VT without a change in the dose. Studies have shown that low expression of interleukin 17 (IL‐17), and tissue necrosis factor alpha (TNF‐ α ) in GCM and other granulomatosis diseases can cause loss of plakoglobin (a desmosomal protein) from intercalated disks . Low level of plakoglobin has been linked with arrhythmogenic right ventricular dysplasia, sarcoidosis, GCM, and other disorders associated with ventricular arrhythmia .…”